As the box board proceeds along a flexible arm or lifter turns the front sides upward, then the sides are folded through formers or other front lifters. To fold up the rear sides and the flaps of the box, electronic timing devices with sensors are used. These rear folding attachments for a machine such as the Babst Media 68 Gluer.sup.* are extremely expensive and prone to problems as the timing and sensors often get out of adjustment and must be readjusted or changed for various sizes of boxes being made. FNT .sup.* Trade mark
The present invention eliminates the need for the very costly and expensive rear side folder mechanism by providing a very simple self-driven attachment which can be mounted on the machine.
In its simplest embodiment, the attachment comprises a self-driven endless chain mounted on sprockets. Push plates are mounted on the chain by couplings. On the opposite end of the push plate a folder lifter arm of spring steel is mounted. The sprockets are mounted on a frame and the frame is then mounted onto the machine.
In a commercial embodiment, three sprockets are used with an endless driving chain with three push plates and three lifting arms. The lifting arms point in the opposite direction to the push plate. The attachment or device is positioned on the machine such that as the box board progresses along the conveyor line, the front end of the box board strikes one of the push plates and moves the endless driving chain forwardly. As the box board progresses further, a lifter arm attached to another push plate swings around the front sprocket of the chain and in an upwards movement lifts and folds the rear side or flap of the box.
Usually two chains each equipped with push plates and folder lifter arms are mounted in parallel relationship to simultaneously use two lifters at one time to fold the rear side or two lifters to simultaneously fold a right and left rear flap.
In a more complex embodiment of the invention, a first chain mounted on sprockets is equipped with pushers and a second chain also mounted on sprockets is equipped with one or more folder lifter arms only. A connecting chain mounted on sprockets connects the first chain with the second chain. In this embodiment, the attachment is mounted above the conveyor and the folder lifter arm lifts and pulls forward the rear side or flap of the box into a folded position.
It is therefore an object of this invention to eliminate a complex and expensive electronically controlled and timed rear folder and to provide a simple attachment of low cost that requires no adjustment other than to accommodate varying box sizes.